No, injecting different blood won’t change
the offspring of an animal. I can see where you
would get the idea that blood carries
information to the next generation. People talk
about “blood relatives” and “bloodlines.” But
these sayings are just leftovers from old ideas
that were disproven long ago, like thinking that
loves happens in your heart instead of your
brain. Injecting blood into an animal does not
change the information that the animal passes to
its offspring. To understand why, let’s go back
to the start of an animal’s life.
Frogs, birds, and humans all start out as a
fertilized egg. This cell has a complete set of
DNA for making the individual frog, bird, or
whatever. This one cell divides, making two
identical cells. They both divide, and so on.
But then cells start to specialize. Some cells
will go on to be reproductive cells (either eggs
or sperm) other cells will go on to be bone
cells or skin cells or blood cells. All the
cells still have the same complete set of DNA,
but some of it is switched off. This all
happens as the individual goes from being one
cell to a ball of cells, to something that looks
like a baby bird, tadpole, or whatever. The DNA
in those egg and sperm cells may occasionally be
changed by mutation, but that’s just a mistake
in copying the DNA.
The idea that what happens in your life
changes your offspring is wrong, but many people
sort of believe it without realizing it. For
example, they may think that if you run a lot,
you will have a child who is fast, or if we get
our wisdom teeth pulled, our children will be
born without them. This is not true. Only
changes in the DNA of egg or sperm cells will
change the information used to make the next
Why do you think people hundreds of years ago
thought blood was so critical? What are the
many things that blood does for us?
Thanks for asking,
The frog's body would probably reject the
bird's blood. What this means is that the frog's
body (as is typical of most organisms)
recognizes what objects are "self" vs. "foreign"
through different chemical signals. Furthermore,
although there is genetic information in our
blood, only the genes carried in our gametes
(also known as reproductive or sex cells) can
transfer genetic information to offspring.
If you injected bird blood into a frog, you
would just have a frog that had some bird
blood. It might get sick from the bird blood,
because its body would know that this was
strange blood that didn't belong in a frog.
My mother-in-law got a new heart valve, and
used a pig valve that they sewed into her
heart! I don't know what they did to the pig
valve, so that my mother-in-law didn't get sick
from having a pig valve in her heart; but I'm
sure they washed it clean and removed all the
blood! Maybe my mother-in-law took medicines,
too, so that her body wouldn't be able to fight
so hard against the pig valve tissue in it.
Keep asking questions!
No. First, you would kill the frog you
the blood into because you would trigger an
immune response against the bird blood you
injected. Even if the frog survived, the blood
would not have gotten into the line of cells
that made sperm and/or eggs, which is what
determines the DNA of the baby frog, so the baby
would still be just a frog.
Click Here to return to the search form.